A part of a process for mounting a die (a semiconductor chip) (hereinafter merely called die) on a board such as a wiring board and a lead frame and assembling a package includes a process for dividing a semiconductor wafer (hereinafter merely called wafer) into dies and a die bonding process for mounting the divided dies on the board.
The bonding process includes a peeling process for peeling the dies divided from the wafer. In the peeling process, these dies are peeled one by one from a dicing tape held on a pickup device and are fed onto the board using an adsorption jig called a collet.
In the related art for executing the peeling process, techniques disclosed in JP-A-2002-184836 and JP-A-2007-42996 for example are described. JP-A-2002-184836 discloses technique for peeling by installing a first group of thrusting pins provided at four corners of a die and a second group of thrusting pins each end of which is lower than that of the first thrusting pin and which are provided to the center or a circumference of the die in a pin holder and raising the pin holder.
Further, JP-A-2007-42996 discloses technique for sequentially thrusting up three blocks by providing the three blocks the thrust height of which can be raised toward the center of a die and providing a projection integrated with each of four corners of the outermost outside block and protruded in a direction of a corner of the die.
Recently, to promote the high density packaging of semiconductor devices, the thinning of a package is in progress. Particularly, a stacked die package in which plural dies are three-dimensionally mounted on a wiring board of a memory card is realized. When such a stacked die package is assembled, the thickness of the die is demanded to be 20 μm or less so as to prevent an increase of the thickness of the package.
When the die is thinned, the rigidity of the die is extremely reduced, compared with the adhesive strength of a dicing tape. Therefore, in the method using the two-stage first and second thrusting pins different in height disclosed in JP-A-2002-184836 or in the method using the multi-stage blocks provided with the projections disclosed in JP-A-2007-42996, the die is also peeled at a stretch from its periphery or its corner. When the die is peeled at a stroke, an effect of anchoring that obstructs peeling, that is, stress concentrates at the periphery or the corner of the die and when the die is thinned to the above-mentioned thickness, the periphery or the corner of the die is deformed and the die is broken. Particularly, when a die attach film exists between the die and the dicing tape, adhesive strength between the dicing tape and the die attach film may be stronger than that between the die and the dicing tape due to the effect of anchoring increased by dicing the die attach film. Further, stability is not acquired and the peeling of the die becomes difficult.